Assembly and method for separating gas from flowing liquids

ABSTRACT

The invention relates to an assembly and a method for separation of gas-containing liquids handled in a process industry. The invention is characterized in that, for the separation of entrained gas, particularly air ( 9 ), or partial removal thereof, from a liquid flow ( 7 ), the apparatus includes a liquid-flow guide ( 2 ) adapted substantially close to the lower end of an inlet pipe ( 1 ) discharging the gas-containing liquid into a container.

[0001] The present invention relates to an assembly in accordance with the preamble of claim 1 for separating gas from flowing liquids handled in a process industry.

[0002] Gases such as air entrained in liquids handled in a process industry are often problematic. The complications occur most frequently in the pumping or measurement of liquids. Gas, particularly air, carried abundantly along with liquids complicates measurements imposed on liquids whereby typically the sensing results become inaccurate and unreliable. Moreover, since air also causes other process complications such as microbial growth, it is most advantageous to separate entrained air.

[0003] Conventionally, gas separation from flows of minor volumetric rate has been carried out by passing the end of a pipe under the surface of water. The purpose of keeping the pipe end submerged under water is to form a water trap to the outlet of the pipe. However, a problem arises at high flow rates therefrom that water can transport the air as bubbles along with its flow, whereby gravity buoyancy of the bubbles does not impart them a sufficient large upward velocity to move them against the flow fast enough to overcome the downward velocity of the water flow.

[0004] The present invention is directed to provide an arrangement capable of eliminating the above-described problems. It is a particular object of the invention is provide both an apparatus and a method for separating gas from a liquid. The characterizing features of the invention are disclosed in the appended claims specifying a novel arrangement for separating gases from a liquid handled in a process industry.

[0005] More specifically, the assembly for separation of gas-containing liquids, particularly for separating air therefrom, is characterized by having a liquid-flow liquid into a container.

[0006] In the following, the invention is described in more detail with the help of an exemplary embodiment by making reference to the appended drawings in which

[0007]FIG. 1 a flow guide according to the invention for separating gas from the flow of gas-containing liquids handled in a process industry;

[0008]FIG. 2 shows an embodiment of a liquid flow measurement arrangement according to the invention; and

[0009]FIG. 3 shows an embodiment of a liquid flow receiver container according to the invention.

[0010] Now referring to FIG. 1, a guide 2 of a liquid flow 7 is mounted essentially to the lower end of an inlet pipe 1 discharging gas-containing liquid into a container. The height position of the flow guide 2 in the vertical direction is adjustable with the help of fixture means 13 for optimizing the separation efficiency. Depending on the type of the liquid being handled in the process, the shape of flow guide 2 can be made essentially flat, upward concave or downward convex. Advantageously, the bottom of the flow guide 2 is made concave so that its edges are curved upward toward the liquid level surface. More precisely, the flow guide 2 is made from sheet metal, perforated plate or sheet material having a desired contour such as undulated plate. As shown in FIG. 1, the flow guide 2 is advantageously mounted on support rods 10 or the like elements that displace the flow guide substantially at a distance from the lower end of the inlet pipe 1. The shape and material of the flow guide can be varied as required. The optimum dimensions of the flow guide are determined by several design factors such as the kind of fluid flowing in the process, the viscosity, temperature, gas/air concentration 9 thereof and the help of laboratory tests.

[0011] In FIG. 2 is shown a preferred exemplary embodiment adapted for flow measurements, whereby the function of the flow guide 2 is to deflect the liquid flow 7 so as to direct the flow toward the liquid level surface. The flow guide 2 makes it easier to direct the liquid flow 7 formed by water with entrained air upward toward the liquid level surface thus facilitating the separation of air 9 from water 7 in order to further provide a solid flow 8. Herein it must be understood that in a conventional arrangement the liquid flow 7 takes place in a consistently downward direction which makes the separation of air bubbles 9 very difficult. Further aiding the function of flow guide 2 in the embodiment according to the invention, the design of a container 11 serving as a liquid receiving vessel is advantageously made such that the flow velocity becomes sufficiently slow to augment the separation of air bubbles 9. Additional stabilization of the solid flow 8 is gained from the use of a partition 3 and a narrow channel 6 at the bottom of the container.

[0012] In FIG. 3 is shown an exemplary embodiment wherein the flow guide 2 is adapted to a gas-separating container. In this example, the flow guide 2 is mounted essentially in the fashion as in FIG. 1 to the lower end of an inlet pipe 1 discharging gascontaining liquid into a container. On the abovedescribed grounds, this embodiment according to the invention can be used in a great number of applications dealing with a liquid flow 7 carrying entrained gas, most typically air 9, that is desired to be efficiently separated or at least reduced down to a suitable level. In a process industry, such problems are encountered probably most frequently in the pumping of liquids and measurements performed thereon. The inventive spirit of the present arrangement is based on guiding air 9 and other entrapped gas bubbles toward the surface level of a liquid container thus augmenting and speeding up the removal of entrained gas. The arrangement according to the invention can be used in almost any type of inlet pipe 1 of measurement vessels and augmented.

[0013] To a person skilled in the art it is obvious that the invention is not limited by the above-described exemplary embodiments, but rather may be varied within the inventive spirit and scope of the appended claims. 

What is claimed is:
 1. An assembly for separation of gas-containing liquids handled in a process industry, characterized in that, for the separation or partial removal of liquid-entrained gas, particularly air (9), from a liquid flow (7), the assembly comprises a liquid-flow guide (2) adapted substantially close to the lower end of an inlet pipe (1) discharging the gas-containing liquid into a container.
 2. The assembly of claim 1, characterized in that the height position of the flow guide (2) is made adjustable in order to optimize the measurement of gas-containing liquids, most advantageously in pulp, board and paper industries e.g., in a white-water or stock container, and to enhance separation of air (9) therein.
 3. The assembly of claims 1-2, characterized in that air separation performed by the flow guide (2) in the assembly is augmented with the help of a partition (3) having a bottom flow channel (6) provided therewith so as to pass the liquid from a receiving chamber (11) further to another chamber (12).
 4. The assembly of claims 1-3, characterized in that on an outer wall (5) of the chamber (12) is provided a weir (4).
 5. The assembly of claims 14, characterized in that the flow guide (2) is shaped so as to guide the air-containing liquid flow (7) essentially upward toward the surface of the liquid level.
 6. The assembly of claims 1-5, characterized in that the bottom of the flow guide (2) most advantageously has a concave shape with its edges curving upward toward the surface of the liquid level or, alternatively, as required by the properties of the liquid handled in the process, is shaped either as a flat plane or with a downward convex shape.
 7. The assembly of claims 1-6 characterized that the flow guide (2) is made from sheet metal, perforated plate or other sheet material having a desired contour such as undulated plate and that the flow guide (2) is most advantageously mounted on support rods (10) that displace the flow guide substantially at a distance from the lower end of the inlet pipe (1).
 8. A method for separation of gas-containing liquids handled in a process industry, characterized in that, in the method for separation of gas-containing liquids particularly free from air (9), the gas-containing liquid is directed to impinge on a liquid-flow guide (2) adapted to the lower end of an inlet pipe (1) discharging the gas-containing liquid into a container, thus accomplishing enhanced separation of air (9) from the liquid flow (7).
 9. The method of claim 8, characterized in that the height position of the flow guide (2) is made adjustable in order to optimize the measurement of gas-containing liquids, most advantageously in pulp, board and paper industries, e.g., in a white-water or stock container, as well as to enhance separation of air (9).
 10. The method of claim 9, characterized in that in the method the flow guide (2) serves to guide the air-containing liquid flow (7) essentially toward the surface of the liquid level in order to enhance separation of air (9) from the liquid flow (7) so as to obtain a solid flow (8).
 11. The method of claim 7, characterized in that according to the method the flow-receiving chamber (11) is dimensioned for a sufficiently slow liquid flow velocity to permit separation of air (9) from the liquid flow (7).
 12. The method of claims 7-9, characterized in that according to the method the solid flow (8) having the entrained air (9) separated therefrom is passed via a bottom flow channel (6) to another chamber (12).
 13. The method of claims 7-10 characterized in that according to the method the separated solid flow (8) is passed via a weir (4) made to the outer wall (5) of the chamber (12) to further process steps. 